Substrate Size Research Articles

Size effects and optimization during laser directed energy deposition on high thermal conductivity copper alloys

High-copper alloy/nickel-based high-temperature alloy bimetallic structures are widely utilized in critical components, such as thrust chambers of liquid rocket engines, water cooling circuits for fusion reactor deflectors, and electromagnetic railguns. Among various methods for fabricating Cu/Ni bimetallic structures, laser directed energy deposition (LDED) is considered one of the most promising techniques for depositing nickel-based high-temperature alloys onto high-copper alloy surfaces. In the LDED fabrication process, substrates with uneven thicknesses are a common. The process is characterized by its multi-parameter, high-sensitivity, and non-equilibrium solidification characteristics. Consequently, variations in substrate size can significantly affect molten pool morphology and fabrication stability. This study examines the size effect of a single track of LDED Inconel 718 (In718) on a CuCr0.8 high-copper alloy substrate. The results indicate a pronounced size effect when using a high thermal conductivity CuCr0.8 substrate, particularly regarding substrate thickness. By reducing the thermal conductivity of the CuCr0.8 substrate, the size effect is mitigated, improving the process adaptability of LDED. These findings provide valuable data for the laser processing of surfaces with uneven thickness and high thermal conductivity. They are expected to support the fabrication of variable thrust liquid rocket engines and advance the field of interplanetary exploration.

Design of low-cost humidity sensor based on chipless RFID

It is of great significance to design a low-cost chipless radio frequency identification(RFID) sensor for environmental humidity monitoring. To this end, polyvinyl alcohol (PVA) film is used as a humidity sensitive material, and the overall size of the rectangular substrate is 18 mm × 18 mm ×0.5 mm. Through the humidity sensing principle and simulation analysis, the change of environmental humidity causes the change of the dielectric constant of the humidity sensitive material PVA, which in turn affects the resonant frequency offset of the entire sensor. The simulation results show that the relative humidity working range of the designed humidity sensor is 21.9% ∼ 52.5%, the corresponding sensor resonant frequency range is 2.76 ∼ 2.51GHz, the total offset reaches 250 MHz, and the average sensitivity at the maximum relative humidity is 23.08MHz/% . The designed humidity sensor has the advantages of miniaturization, simple structure and low cost, and can be used for humidity monitoring in various target environments. Keywords.low cost; chipless RFID humidity sensor; polyvinyl alcohol; humidity monitoring; humidity sensitive material.

Atypical Presentation of Dysembryoplastic Neuroepithelial Tumor

Dysembryoplastic neuroepithelial tumor (DNET) is a benign glioneuronal neoplasm, usually found in children and adolescents, in the vast majority of cases associated with drug-resistant epilepsy. Typically, epileptic seizures are the main, and in most cases, their only clinical manifestation. Although DNET is a benign, biologically stable tumor with few reports of malignancy, it is one of the most common reasons for epileptic surgery. The epileptogenic potential of this tumor is so high that DNET s, along with ganglioglioma, have received the informal term “epileptomas” and are by far the leaders in the group of low-grade tumors associated with long-term epilepsy-associated tumors (LEAT). It is believed that this epileptogenicity is due to localization in the neocortex and frequent association with focal cortical dysplasias (FCD). In the world literature, there are only a few mentions of DNET s not associated with epilepsy. The article presents the experience of complex, interdisciplinary diagnosis of DNET in a child without epilepsy who complained of frequent headaches. During a comprehensive MRI examination, a cortical-subcortical pathological substrate was discovered in the left temporal lobe with radiological signs of DNET. During video-EEG monitoring of night sleep, no epileptiform signs were recorded. There was no history of epileptic seizures or other paroxysms. A control MRI revealed a slight increase in the size of the pathological substrate, which was the reason for surgical treatment. Pathological examination revealed microscopic features of DNET. This case of absence of epilepsy in a child with cortical DNET in the temporal lobe cortex suggests that the spectrum of its clinical manifestations and biological behavior is not fully understood and requires further comprehensive study.

Disruption of natural disturbance regime decouples habitat and life stage in a keystone species

AbstractAnthropogenic disturbance of stream ecosystems, often chronic in nature, has been studied extensively. However, when disturbance is driven by more than one resource policy over many decades, feedback between habitat evolution and biological adaptation can be disrupted and ecological function affected in unforeseen ways. We analyzed over 100 years of Chinook salmon (Oncorhynchus tshawytscha) length frequency trends associated with fisheries management and changes in available spawning substrate (habitat) linked to flow regulation in a highly altered California river. Over time, salmon lengths generally decreased, fluctuating with exploitation (ocean harvest) and hatchery production rates. Female size reduction, coupled with a degrading and coarsening channel, and perching peripheral habitat related to past mining activity, indicates available spawning substrate may be too large to support the current salmon population. Assuming a salmon can move material ~10% of her body length, length frequency data and current substrate size distribution suggest that increasing salmon sizes to historic distributions could increase available spawning habitat by as much as 13%. Alternatively, decreasing spawning substrate size could support a greater portion of the current population. To test the latter hypothesis and inform future management actions, we monitored two spawning riffles where large and small gravel was placed on top of a cobble. We observed an immediate spawning activity increase that was more pronounced where smaller gravel was deposited. Following a decade of habitat decline, the two sites were both replenished with medium gravel. Elevated spawning use occurred immediately at both sites, commensurate with this intermediate size, further supporting our hypotheses. Sediment coarsening and habitat disconnect below dams, combined with reduced salmon size, indicate the natural spawning process may be decoupled from available habitat below dams in the foreseeable future without continuous intervention. Actively managing salmon population demographics through modified hatchery and size‐selective harvest practices and developing a coarse sediment budget with size‐appropriate material for regulated anadromous rivers could produce immediate benefits for ecosystem services, including salmon populations. However, these management actions will require continued maintenance and informed socio‐ecological goals to remain successful.

Asymmetric competition for habitats between the temperate Japanese eel Anguilla japonica and the tropical Indo-Pacific eel A. marmorata

Habitat segregation is a common phenomenon among anguillids in rivers where multiple species coexist. However, despite the growing need to conserve their river habitats, the mechanisms underlying such segregation remain unknown. Here, we conducted tank experiments to investigate the competitive superiority for habitats between the temperate Japanese eel Anguilla japonica and the tropical Indo-Pacific eel Anguilla marmorata, which co-occur in East Asian subtropical rivers. Using eight interspecific pairs of these two species of comparable total length, we compared the use of a single pipe shelter, recorded over a 24-h experimental period, between solitary and paired conditions. The changes in shelter use patterns between conditions indicated that in the paired condition, the shelter was occupied by A. marmorata in five pairs (62.5%) by the end of the experiment while A. japonica appeared to occupy the shelter in only one pair (12.5%). Furthermore, agonistic behaviors, which occurred mainly at night, such as biting and head-butting, were observed much more frequently for A. marmorata toward A. japonica (mean ± standard deviation: 23.2 ± 36.6 times per individual) than for A. japonica toward A. marmorata (0.4 ± 0.5 times per individual), indicating an asymmetry in aggressiveness. These results suggest that A. marmorata can negatively affect the diurnal habitat use and nocturnal activities of sympatric A. japonica. These findings, combined with those from previous field studies, suggest that A. marmorata may competitively exclude A. japonica from stream habitats with large substrate sizes. This asymmetric competition can contribute to shaping their riverine distribution and composition within rivers where they co-occur.

Substrate specificity of a branch of aromatic dioxygenases determined by three distinct motifs

The inversion of substrate size specificity is an evolutionary roadblock for proteins. The Duf4243 dioxygenases GedK and BTG13 are known to catalyze the aromatic cleavage of bulky tricyclic hydroquinone. In this study, we discover a Duf4243 dioxygenase PaD that favors small monocyclic hydroquinones from the penicillic-acid biosynthetic pathway. Sequence alignments between PaD and GedK and BTG13 suggest PaD has three additional motifs, namely motifs 1-3, distributed at different positions in the protein sequence. X-ray crystal structures of PaD with the substrate at high resolution show motifs 1-3 determine three loops (loops 1-3). Most intriguing, loops 1-3 stack together at the top of the pocket, creating a lid-like tertiary structure with a narrow channel and a clearly constricted opening. This drastically changes the substrate specificity by determining the entry and binding of much smaller substrates. Further genome mining suggests Duf4243 dioxygenases with motifs 1-3 belong to an evolutionary branch that is extensively involved in the biosynthesis of natural products and has the ability to degrade diverse monocyclic hydroquinone pollutants. This study showcases how natural enzymes alter the substrate specificity fundamentally by incorporating new small motifs, with a fixed overall scaffold-architecture. It will also offer a theoretical foundation for the engineering of substrate specificity in enzymes and act as a guide for the identification of aromatic dioxygenases with distinct substrate specificities.

A low‐profile, wideband, circularly polarized, slotted, U‐shaped textile antenna for W‐BAN applications

AbstractWe propose a compact, wideband, U‐shaped, circularly polarized textile antenna (UCPTA) resonating at 2.45 GHz for wireless body area network (W‐BAN) applications. The radiator of the antenna is printed on the top of the substrate (size of mm3; ) and has a full ground plane on the other side. The proposed antenna's substrate consists of a single layer of denim (), and conductive copper tape was used to fabricate the patch. The antenna has a low‐profile design that is suitable for wearable applications. A small slot was introduced at the center of the U‐shaped patch to enhance the 3 dB axial ratio bandwidth (ARBW) up to 55.17%. The proposed antenna radiates with a 10 dB return loss (RL), impedance bandwidth (IBW) of 64.40%, and a simulated gain of 5.1 dBi. The wearable textile antenna with broadside radiation response is appropriate for off‐body communications. The prototype of UCPTA is fabricated for experimental validation. The measured results for the fabricated antenna were in good agreement with the simulated results. Further, it has been demonstrated that the antenna's performance is stable during structural deformation and human body loading. This textile antenna covers an ARBW in the frequency band of 2.1 GHz–3.72 GHz and has a broad IBW (2 GHz–3.9 GHz) for LTE (2.17 GHz), MBAN (2.360 GHz–2.4 GHz), WPAN (2.395 GHz–2.4 GHz), and WLAN (2.4 GHz–2.482 GHz) applications.

Coordinating the pore size of paper substrates and aspect ratio of silver nanowires to improve printed electronics

The internet of things is advancing toward a world of ubiquitous electronic devices, composed in large part of low-cost printed electronics (PE) such as sensors. PE typically use plastic substrates, such as polyethylene terephthalate (PET), but these materials are not biodegradable. The proliferation of PE devices and their degradation to form micro- and nanoplastics pose significant environmental hazards. Paper is a promising substrate to replace PET for greener PE due to its recyclability, affordability, and compatibility with many printing processes. However, the porous cellulosic structure of paper can be an obstacle when trying to print active inks due to wicking of the ink into the paper pores, which disperses the functional ink and negatively impacts electronic performance. Filling the pores of paper with a polymer to planarize the surface is a commonly used remedy, although this approach can compromise recyclability. Here, we present an approach to manage the dispersion of silver nanowires, a widely used and printable 1D nanomaterial ink, in paper substrates. We deposit solutions of short (20–30 μms) and long (100–200 μms) silver nanowires onto various graded filter papers that differ in pore size and examine the trends in wicking distance, wicking speed, and electrical properties. We show that with careful selection of AgNW length and the pore size of the paper, it is possible to control the lateral spreading of the ink and minimize the concentration of the AgNWs needed to achieve a specific electrical performance.

Quantifying form resistance is essential for estimating summer low and bankfull flow from stream survey channel morphology

Reliable estimates of low flow and flood discharge at ungaged locations are required for evaluating stream flow alteration, designing culverts and stream crossings, and interpreting regional surveys of habitat and biotic condition. Very few stream gaging stations are located on small, remote streams, which typically have complex channel morphology. Adequate gaging is also lacking on larger streams that are remote, smaller than those typically gaged, or have channel morphology not conducive to installation of gages. Complex channels typically contain large scale hydraulic roughness elements that dominate flow patterns (i.e., form roughness), making it difficult to measure channel cross-section area and water velocity, or to measure channel volume even where discharge is known. In channels with large channel form roughness, it is equally difficult to estimate discharge using commonly applied equations based on slope and channel dimensions or basin area. We employed a novel approach that explicitly accounts for hydraulic resistance from large wood and riffle-pool morphology (form roughness) in calculating low flow and bankfull discharge from stream and river physical habitat data collected from 4229 stream and river sites in the conterminous US (CONUS) sampled in 2008–9 and 2013–14 as part of the US Environmental Protection Agency's National Rivers and Streams Assessment (NRSA). Hydraulic resistance derived from form roughness clearly dominated resistance derived from bed particles (particle resistance) during summer low flows in wadeable streams across the spectrum of channel slopes and substrate sizes smaller than boulders. Under bankfull conditions, the influence of form resistance relative to particle resistance was diminished, but form resistance still dominated except in large low gradient rivers lacking complex channels, and in streams or rivers with boulder-size bed particles. We validated our hydraulic resistance estimates by comparing measured discharges with calculated discharges that used those hydraulic resistance estimates along with measured NRSA channel morphology data. Morphology-based summer discharge (low flow) estimates and direct field measurements of discharge in 2333 wadeable CONUS streams showed reasonable agreement (median difference < 2.5×) for discharges ranging from 3.6 × 10−5 to 123 m3/s and drainage areas of 0.12 to 171,000 km2. In a subset of 759 of NRSA's larger wadeable stream and non-wadeable river sites where nearby U.S. Geological Survey (USGS) gage data were available and adequate, our morphology-based summer discharge estimates agreed fairly well (median difference < 2.0×) with USGS 20-yr average August mean flows ranging from 0.003 to 16,000 m3/s. Similarly, morphology-based estimates of bankfull flow ranging from 0.3 to 100,000 m3/s agreed reasonably well with the 1.5-yr recurrence interval flood in these gaged sites (median deviation <2.2×). These findings demonstrate the importance of quantifying flow resistance from large-scale form roughness features in natural channels and provide a novel approach for estimating discharge from widely available survey data. This will allow examination of discharge and its ecological influence across the full range of stream and river sizes sampled by NRSA or other synoptic surveys where comprehensive measures of biota, physical habitat, and chemistry are also made. Although these morphology-based estimates exhibit some variability, they are adequate for examining regional patterns in discharge and flow alteration and their association with instream biota and anthropogenic disturbances, providing summer low and bankfull flow information where reliable estimates are lacking.

Machine learning method for roughness prediction

This work aims to employ machine-learning models, specifically neural networks, to predict the time evolution of the global surface roughness in a lattice model that represents a film growing on a d-dimensional substrate. We analyze the well-known ballistic deposition (BD) model for d=1, 2 since it presents strong corrections to the scaling, making it difficult to observe directly, via effective scaling exponents, its correspondence with the Kardar-Parisi-Zhang (KPZ) universality class. As an alternative to overcome this difficulty, we first intend to learn the time evolution of the global roughness for substrate sizes that are computationally viable to simulate. To test the learning, we apply two different methodologies for d = 1: the first one learns the Family-Vicsek scaling relation, and by doing the reverse transformation, we get the global roughness as a function of the time, and the second one learns the kinetic roughening directly from the time series data. For growth in d = 2 where applications arise and no exact KPZ scaling exponents are known, we apply the second methodology. However, we employ a more resilient learning model tailored for time series problems. Hence, the time required to generate the same amount of data, showing the evolution of global roughness, is reduced dramatically. Importantly, machine learning techniques capture the scaling corrections of the BD model, predicting an effective global roughness exponent, α, calculated from the learned data extracted from very large lateral sizes and times that cannot be simulated using lattice models. Our prediction is consistent with accurate estimates of the KPZ roughness exponent reported in the literature for d = 2.

Atomic sawtooth-like metal films for vdW-layered single-crystal growth

Atomic sawtooth surfaces have emerged as a versatile platform for growth of single-crystal van der Waals layered materials. However, the mechanism governing the formation of single-crystal atomic sawtooth metal (copper or gold) films on hard substrates (tungsten or molybdenum) remains a puzzle. In this study, we aim to elucidate the formation mechanism of atomic sawtooth metal films during melting–solidification process. Utilizing molecular dynamics, we unveil that the solidification of the liquid copper initiates at a high-index tungsten facet with higher interfacial energy. Subsequent tungsten facets follow energetically favourable pathways of forming single-crystal atomic sawtooth copper film during the solidification process near melting temperature. Formation of atomic sawtooth copper film is guaranteed with a film thickness exceeding the grain size of polycrystalline tungsten substrate. We further demonstrate the successful growth of centimeter-scale single-crystal monolayer hexagonal boron nitride films on atomic sawtooth copper films and explore their potential as efficient oxygen barrier.

Magnetic contrast layers with functional SiO2 coatings for soft-matter studies with polarized neutron reflectometry

This study introduces silicon substrates with a switchable magnetic contrast layer (MCL) for polarized neutron reflectometry (PNR) experiments at the solid–liquid interface to study soft-matter surface layers. During standard neutron reflectometry (NR) experiments on soft-matter samples, structural and compositional information is obtained by collecting experimental data with different isotopic contrasts on the same sample. This approach is normally referred to as contrast matching, and it can be achieved by using solvents with different isotopic contrast, e.g. different H2O/D2O ratios, and/or by selective deuteration of the molecules. However, some soft-matter systems might be perturbed by this approach, or it might be difficult to implement, particularly in the case of biological samples. In these scenarios, solid substrates with an MCL are an appealing alternative, as the magnetic contrast with the substrate can be used for partial recovery of information on the sample structure. More specifically, in this study, a magnetically soft Fe layer coated with SiO2 was produced by ion-beam sputter deposition on silicon substrates of different sizes. The structure was evaluated using X-ray reflectometry, atomic force microscopy, vibrating sample magnetometry and PNR. The collected data showed the high quality and repeatability of the MCL parameters, regardless of the substrate size or the thickness of the capping SiO2 layer. Previously proposed substrates with an iron MCL used an Au capping layer. The SiO2 capping layer proposed here allows reproduction of the typical surface of a standard silicon substrate used for NR experiments and is compatible with a large variety of soft-matter samples. This application is demonstrated with ready-to-use 50 × 50 × 10 mm substrates in PNR experiments for the characterization of a lipid bilayer in a single solvent contrast. Overall, the article highlights the potential of PNR with an MCL for the investigation of soft-matter samples.

Single-atom catalysts on ceria substrates: Exploring cluster and surface effects on methane activation

The activation of methane (CH4) is a critical step in its conversion to high value products, which require the use of catalysts due to the higher stability of the C-H bond. In this study, we combined density functional theory calculations and the unit bond index-quadratic exponential potential approximation to investigate the first CH4 dehydrogenation in the TM/(CeO2)10 system, where TM represents a single transition-metal specie (Fe, Co, Ni, Cu) supported in the compact (CeO2)10 cluster. In addition, substrate size effects will be addressed by comparing our results with previous surface science studies by our group. We found a direct correlation between the magnitude of the TM adsorption energy on the CeO2 substrates (hollow and bridge sites) and the magnitude of charge transfer from the TM adatoms to the substrates, while CH4 has a weaker physisorption binding energy to the ceria cluster and the surface substrates. Molecular fragments derived from CH4 (CH3 and H) bind through chemisorption interactions to the TM and O sites, respectively. The estimated energy barrier for the cleavage of the C-H bond is lower when the reaction occurs in the cluster rather than on the surface. The molecular fragments exhibited better stabilization on cluster substrates, resulting in an exergonic dehydrogenation reaction; whereas, for surfaces, the reaction was endergonic. Among the selected TM species, Fe and Co adatoms are promising candidates for the first CH4 dehydrogenation on CeO2 substrates, which can be explained by the magnitude of the metal-support interaction and stabilization of the CH3 specie, which results in the lowest barriers among the evaluated transition metals.

Enhancement of Cu-to-Cu bonding property by residual stress in Cu substrate

This study investigated the use of copper nanoparticles (Cu NPs) as a novel material for interconnecting joints in advanced electronic packaging technology. Cu NPs offered a promising alternative due to their excellent electrical and thermal properties. Cu NPs were characterized as single crystals by a transmission electron microscope, and electron backscatter diffraction confirmed that the grain size of the Cu substrate was about 11 μm and only became slightly larger after thermal annealing. Surface diffusion was determined to be the dominant kinetic path for Cu NP sintering on the substrate. An additional driving force for sintering was validated by measuring the stress state using X-ray diffraction. The characterization results provided evidence for proposing a mechanism to explain how residual stress influenced atomic behavior during the sintering process. High residual stress enhanced the strength of the Cu NP joints and improved the reliability of electronic devices.

Process and production enhancement through codigestion in biogas generation

AbstractPakistan is facing a major challenge in the domestic gas and energy sector, and its demand is continuously growing. It is imperative to produce more energy in the form of gaseous resources and electricity to reduce this energy crisis in the future. The current work is related to studying various factors that play a critical role in enhancing the process and production of biogas. The effect of codigestion, substrate size, temperature, pH, and catalyst addition are important parameters. Three batch processes are conducted for 21 days under mesophilic conditions, which is easier to achieve as compared with the thermophilic one. Codigestion of cow manure combined with food, poultry waste, and sewerage water showed some promising results compared with a single substrate (cow dung). This results in the production of biogas of about 120 L. The particle size is then reduced to 5 mm, which leads to an increase in the available surface area for microbial attack and hence increases and enhances further the process and production of biogas. However, the addition of 250 g of silica gel increases production by up to 17%. The better value for the pH range for this batch was found in the range of 6.5–7.8. The codigestion would help in cost‐effective and more efficient waste treatment. The digestate in all the batch processes comes out enriched in nitrogen that is used as an organic fertilizer.

Intra-chloroplast proteases: A holistic network view of chloroplast proteolysis.

Different proteases and peptidases are present within chloroplasts and nonphotosynthetic plastids to process precursor proteins and to degrade cleaved chloroplast transit peptides and damaged, misfolded, or otherwise unwanted proteins. Collectively, these proteases and peptidases form a proteolysis network, with complementary activities and hierarchies, and build-in redundancies. Furthermore, this network is distributed across the different intra-chloroplast compartments (lumen, thylakoid, stroma, envelope). The challenge is to determine the contributions of each peptidase (system) to this network in chloroplasts and nonphotosynthetic plastids. This will require an understanding of substrate recognition mechanisms, degrons, substrate, and product size limitations, as well as the capacity and degradation kinetics of each protease. Multiple extra-plastidial degradation pathways complement these intra-chloroplast proteases. This review summarizes our current understanding of these intra-chloroplast proteases in Arabidopsis and crop plants with an emphasis on considerations for building a qualitative and quantitative network view.

Boosting efficiency of mussel spat collection for ecological sustainability: Identifying critical drivers and informing management

Abstract The long‐term sustainability of natural and bottom‐cultured mussel beds relies on the availability of spat (i.e. juvenile mussels). Traditional spat collection methods, which disrupt the donor population and its habitat, have prompted the adoption of suspended mussel spat collectors (SMCs) as an ecologically sustainable alternative. However, practical experience has demonstrated that SMC efficiency is subject to significant spatiotemporal variability, with the underlying biotic and abiotic drivers remaining unresolved. Based on 11‐year SMC practices in the Dutch Wadden Sea, we first validated, through field experiments, the inference that larval abundance and settlement rate in seawater are the primary determinants of SMC efficiency. Secondly, we screened the key factors driving variation in SMC efficiency using an integrated dataset that includes both management options (i.e. user‐defined factors, like SMC types) and environmental conditions (i.e. site‐specific factors, such as hydrodynamics). Lastly, we developed a predictive model to explore the sensitivity of SMC efficiency to these key factors. The efficiency of SMCs was not affected by larval abundance and settlement rate, but rather regulated by management options and environmental conditions, with the key factors identified as SMC type, substrate size, mean wave height and starfish abundance. Rope‐based SMCs outperform net‐based SMCs in terms of harvest efficiency. Both types of SMCs exhibit consistent sensitivity to environmental conditions, with harvest efficiency higher in areas with lower mean wave height and fewer starfish. Increasing substrate size (i.e. rope length and net area) in these areas has the potential to further improve SMC efficiency. Synthesis and applications: Our study highlights the importance of environmental conditions over life cycle‐related factors in regulating SMC efficiency. This offers optimistic prospects for investment in larger‐scale deployment of SMCs and maximizing efficiency through site suitability assessments beforehand. The predictive model we developed can provide information for this purpose. Furthermore, strategically adjusting management options would further optimize SMC efficiency, but it is necessary to balance the associated benefits and costs. Overall, our study underscores the predictability and controllability of SMC efficiency and informs management to maximize sustainable spat supply in both mussel culture and restoration.

Influence of the Substrate Size on the Cooling Behavior and Properties of the DED-LB Process

Influence of the Substrate Size on the Cooling Behavior and Properties of the DED-LB Process

Effects of Rock Type and Food Availability on Bioerosion by the Purple Sea Urchin, Strongylocentrotus purpuratus.

Purple sea urchins (Strongylocentrotus purpuratus) profoundly impact nearshore rocky coasts through their feeding habits. Their intense grazing sculpts substrates through bioerosion using their teeth and spines and controls the alternative stable state dynamic between kelp bed and urchin barrens. These states have contrasting food availability for sea urchins, with abundant food in kelp beds and scarce food in barren grounds. However, the relationship between food availability and bioerosion is unknown. We predicted that when kelp is available, it would ameliorate the action of teeth on the substrate. Our 11-weeks long, 2×2 factorial experiment, crossed community state (kelp present vs absent) and rock type (sandstone vs mudstone). We also quantified the contribution of spine abrasion to bioerosion on the two rock types. The bioerosion rates did not differ between treatments with and without kelp. Although there was no significant difference in net bioerosion between the rock types, there was a large difference between the proportion of bioerosion from teeth vs spine abrasion. Approximately a third of the sandstone bioerosion was from spines whereas less than 2% of mudstone bioerosion could be attributed to spines. As anticipated, growth of sea urchins fed kelp ad-libitum was higher than food-limited sea urchins. Surprisingly, sea urchins on mudstone (which has a higher organic component) grew faster than sea urchins on sandstone. Although bioerosion rates may not differ on a per-urchin basis between community states, the sea urchin population densities between kelp beds and urchin barrens likely causes a difference in net bioerosion between these communities. Our results point to the importance of lithology on the mechanics of sea urchin bioerosion. Differences in texture, grain size, and hardness of rock substrates undoubtedly contribute to bioerosion rates and dynamics.

P‐107: High‐Resolution Periodic Patterning for Volume Manufacturing on +300mm Size Substrates Using Displacement Talbot Lithography

The photonic device market has a need for low‐cost, high‐resolution periodic patterning that scales with product maturity to large substrate sizes. Eulitha's DTL (Displacement Talbot Lithography) technology was limited to only a single exposure field per substrate on preexisting platforms which can fully pattern 100 and 150mm substrates. The new ‘PhableS' is Eulitha's step‐and‐repeat solution to bring all the advantages of the DTL patterning to larger substrates.The PhableS tool builds on Eulitha's patented displacement Talbot lithography technology to open the way for customers to fully scale to high volume production. This tool retains the strong technical performance; including 60nm half pitch resolution (DUV version), 140x140mm2 single shot exposure field, large depth of focus (hundreds of microns), high throughput (+40wph), non‐contact, mask‐based patterning. Automated wafer and mask handling support industry expected repeatability and defect‐free patterning.